System and method for generating a probability value for an event

Abstract

A method and system for generating a probability value for an event. The system includes a source for generating a plurality of digital input signals, a processor connected to the source to receive the plurality of digital input signals from the source, and a display connected to the processor for displaying a final output. Preferably, the method further includes validating the probability value.

Claims

1. A non-transitory computer-readable medium that stores a program that causes a processor to perform functions to generate a probability value for a seizure based on an EEG by executing the following steps: receiving an EEG recording at a first processor, the EEG recording generated from a plurality of EEG signals generated from an EEG machine comprising a plurality of electrodes, at least one amplifier, and a second processor, wherein the EEG recording comprises a plurality of channels corresponding to the plurality of electrodes, each of the plurality of channels comprising a plurality of epochs; submitting the EEG recording to a multilayer perceptron operating on a first processor to generate a plurality of raw score epochs, wherein the multilayer perceptron comprises six inputs, three hidden nodes and a single output; sorting at the first processor the plurality of raw score epochs by similar values; calibrating at the first processor a first half of the plurality of raw score epochs with similar values to generate a probability value that a seizure will occur; validating at the first processor the probability value that a seizure has occurred with actual data; validating at the first processor a second half of the plurality of raw score epochs with similar values at the multilayer perceptron to determine if the probability value is correct; and, generating at the first processor a graph of the probability value versus time on a graphical display.

2. A system for generating a probability value for a seizure based on an EEG, the system comprising: an EEG machine comprising a plurality of electrodes and at least one amplifier; a processor connected to the EEG machine to receive a plurality of EEG signals from the EEG machine; and a graphical display connected to the processor; wherein the EEG recording comprises a plurality of channels corresponding to the plurality of electrodes, each of the plurality of channels comprising a plurality of epochs; wherein the EEG recording is submitted to a multilayer perceptron at the processor to generate a plurality of raw score epochs, wherein the multilayer perceptron consist essentially of six inputs, three hidden nodes and a single output; wherein the processor is configured to sort the plurality of raw score epochs by similar values; wherein the processor is configured to calibrate a first half of the plurality of raw score epochs with similar values to generate a probability value that a seizure will occur; wherein the processor is configured to validate the probability value that a seizure has occurred with actual data of a seizure; wherein the processor is configured to validate a second half of the plurality of raw score epochs with similar values the multilayer perceptron to determine if the probability value is correct; and, wherein the processor is configured to generate a graph of the probability value versus time on the graphical display.

3. A non-transitory computer-readable medium that stores a program that causes a processor to perform functions to determine a probability value for fraudulent credit card transactions by executing the following steps: receiving a plurality of credit card transactions at a server, the server comprising a plurality of peripheral interfaces, a processor, a memory, a storage, a communication module and an output module; submitting to the server the plurality of credit card transactions to a multilayer perceptron to generate a plurality of raw score value for each of the credit card transactions, wherein the multilayer perceptron comprises six inputs, three hidden nodes and a single output; sorting at the server the plurality of raw score values by similar values; calibrating a first half of the plurality of raw score values with similar values to generate a probability value that a credit card transaction was fraudulent; validating at the server the probability value that a fraudulent credit card transaction has occurred with actual data; validating at the server a second half of the plurality of raw score values with similar values at the multilayer perceptron to determine if the probability value is correct; and, generating at the server a graph of the probability value versus time on a graphical display.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a block diagram of a system for generating a probability value for an event.

(2) FIG. 1A is a block diagram of a system for generating a probability value for an event.

(3) FIG. 2 is a flow chart of a method for generating a probability value for an event.

(4) FIG. 3 is a block diagram for generating a probability value for a seizure.

(5) FIG. 4 is a block diagram of a flow chart of determining a probability value for a fraudulent credit card transaction.

(6) FIG. 5 is a block diagram of a flow chart of inputs for generating a raw score for a fraudulent credit card transaction.

(7) FIG. 6 is an illustration of an EEG system used on a patient.

(8) FIG. 7 is a map representing the international 10-20 electrode system for electrode placement for an EEG.

(9) FIG. 8 is a detailed map representing the intermediate 10% electrode positions, as standardized by the American Electroencephalographic Society, for electrode placement for an EEG.

(10) FIG. 9 is a graphical display of the amount of artifact present in an EEG recording.

(11) FIG. 9A is a graphical display of the amount of artifact present in an EEG recording.

(12) FIG. 9B is an enlarged and isolated view of a box 1B of a seizure probability channel of FIG. 9.

(13) FIG. 9C is an enlarged and isolated view of horizontal lines of the artifact intensity channel of FIG. 9.

(14) FIG. 10 is a flow chart of a method for generating a probability value for a seizure.

(15) FIG. 11 is a flow chart of a method for validating a probability value for an event.

(16) FIG. 12 is a block diagram of a computing device for EEG processing.

DETAILED DESCRIPTION OF THE INVENTION

(17) As shown in FIGS. 1 and 1A, a system for generating a probability value is generally designated 100. The system 100 preferably comprises a source 70, a processor 75, and a display 80. The source 70 generates digital input signals, which are received by a processor 75 that is connected to the source 70. The processor 75 is configured to submit the digital input signals to a recognition algorithm 85 to generate a raw score 60. The processor 75 is also configured to calibrate the raw score 60 to generate a probability value 65 that an event has occurred and then to generate a display of the probability value 65 versus time. Further, the processor 75 is configured to validate the probability value 65. The processor 75 is also connected to a display 80 for displaying a final output.

(18) A general method 200 for generating a probability value is illustrated in the flow chart of FIG. 2. At block 201, a plurality of digital input signals is generated from a machine comprising a source, a processor and a display. At block 202, the plurality of digital input signals is submitted to a recognition algorithm to generate a raw score. At block 203, a raw score is calibrated to generate a probability value that an event will occur. At block 204, a graph of the probability value versus time is generated.

(19) FIG. 3 is a block diagram of a specific example of a system 300 for generating a probability value for detecting a seizure from a raw EEG recording. The raw EEG is processed through artifact reduction filters and neural network algorithms to generate raw score epochs that are calibrated to generate a probability value that a seizure is occurring. For example, taking one hundred epochs of one second duration that were given a 20% probability score of a seizure, the system determines if twenty of those one hundred were actually a seizure. This occurs by calibrating fifty of the epochs to measure if seizures occurred in ten of those fifty. The calibration will provide a probability value, which will be validated against the remaining fifty epochs. Next, one hundred epochs of one second duration that were given a 30% probability score of a seizure, the system determines if thirty of those one hundred were actually a seizure. This occurs by calibrating fifty of the epochs to measure if seizures occurred in fifteen of those fifty. The calibration will provide a probability value, which will be validated against the remaining fifty epochs. If fifteen of the remaining fifty evidence a seizure, then the probability value is validated. This also allows for training of a neural network to generate a validated probability value.

(20) In another example, the digital input signals from the source 70 are a value for a fraudulent credit card transaction, a value for a monthly salary income for a loan applicant, a value for monthly rental income for a loan applicant, a value of a collateral for a loan, a value for a monthly car payment for a loan applicant, or a value of a number of years employed for a loan applicant.

(21) Artificial neural networks (ANN) have been used to solve various tasks in numerous fields that are hard to solve using ordinary rule-based programming. An ANN can learn and adapt through learning algorithms. The types of ANNs and ANN architecture varies, mainly in the learning method.

(22) The basic phases of an example algorithm 300 are shown in FIG. 3.

(23) A multilayer perceptron (MLP) is a feed forward ANN. FIG. 5 shows a graphical depiction of the MLP architecture with six inputs (x.sub.1-x.sub.6), three hidden nodes and a single output (y.sub.k). Using a value for a fraudulent credit card transaction as the digital input signal as an example, an ANN can be used to recognize patterns of credit card use. The inputs can be information such as related to the cardholder or to the transactions. Example inputs can include types of purchases, frequency of specific purchases, time of purchase, or where purchases were made. The inputs are processed through the hidden node and then the output is a decision after processing. While the algorithm does not match up the pattern, the purpose is to determine the differences and find a threshold for the difference before determining that the use is fraudulent.

(24) FIGS. 4 and 5 are directed to an embodiment for determining a probability value for fraudulent credit card transactions. As shown in FIG. 4, at stage 510, multiple credit card transactions are performed credit card users. At stage 520, each transaction is transmitted to a server for a credit card company for authorization of each of the charges. The server utilizes an algorithm to generate a raw score value at stage 525. FIG. 5 illustrates some of the inputs utilized in an algorithm to generate a raw score value. The inputs for the algorithm of the example include: location 810, amount 815, frequency of credit card use 820, the timing of the use 830, in-person or by phone 840, and the identification of the merchant 850. These inputs are used to generate a raw score 800. However, those skilled in the pertinent art will recognize that other algorithms will use more or less inputs to generate a raw score without departing from the scope and spirit of the present invention.

(25) Returning to FIG. 4, the raw scores are assorted by similar values, such as 0.1% for one group and 0.05% for another group. Then, half of the raw score values are calibrated to generate a probability value at 550. During the calibration stage, the groups sorted by raw scores are analyzed with the actual data for each credit card transaction in the group to calibrate the raw score value. For example, if all of the credit card transactions with a 0.1% raw score value area analyzed, then only 0.1% of the transactions should be fraudulent. However, if the actual data shows that the true value is 0.095% of the transactions were fraudulent, then the raw score value is calibrated and a probability value for those raw scores values is now 0.0095%.

(26) Next, the other half of the raw scores values are validated with the corrected algorithm using the probability value. If the actual data for this second half of raw scores values demonstrates that the probability value is correct, then the calibrated algorithm has been validated. However, if the validation is incorrect, the process is repeated.

(27) In classification, the task is to a classify a variable y=x.sub.0 called class variable or output given a set of variables x=x.sub.1 . . . x.sub.n, called attribute variables or input. A classifier h:x.fwdarw.y is a function that maps an instance of x to a value of y. The classifier is learned from a dataset d consisting of samples over (x, y). The learning task consists of finding an appropriate Bayesian network given a data set d over U. Let U={x.sub.1, . . . , x.sub.n}, n1 be a set of variables.

(28) In an example for a loan application, there are two classes, low-risk and high-risk applicants. In order to find out if an applicant may default on the loan, a probability is calculated, P(Y|X), where X is the input, such as salary income, and Y is the 0 or 1 to indicate low-risk or high-risk, respectively. For a given X=x, P(Y=1|X=x)=0.9, the probability is 90 percent that the applicant is high-risk.

(29) A perceptron models a biological neuron as a mathematical function,

(30) $y=\underset{j=1}{\overset{d}{.Math.}}{w}_j{x}_j+w_0$

(31) where the weighted sum, y, of the input values, x.sub.j, j=1, . . . , d.sub.j, are calculated. The weights are w.sub.j.

(32) The following is a Perceptron Training Algorithm for training a MLP with K outputs.

(33) TABLE-US-00001 For i = 1,..., K For j = 0,..., d w.sub.ij rand(0.01,0.01) Repeat For all (x.sup.t, r.sup.t) X in random order For i = 1,..., K o.sub.i 0 For j = 0,..., d o.sub.i o.sub.i + w.sub.ijx.sup.t.sub.j For i = 1,..., K y.sub.i exp(o.sub.i) / .sub.k exp(o.sub.k) For i = 1,..., K For j = 0,..., d w.sub.ij w.sub.ij+ (r.sup.t.sub.i y.sub.i )x.sup.t.sub.j

(34) Until convergence

(35) Where is the learning factor.

(36) The following is a Backpropagation Algorithm for training a MLP with K outputs.

(37) Initialize all v.sub.i h and w.sub.h j to rand(0.01,0.01)

(38) Repeat For all (x.sup.t, r.sup.t) in random order For h=1, . . . , H
z.sub.hsigmoid(w.sup.T.sub.hx.sup.t) For i=1, . . . , K
y.sub.i=v.sup.T.sub.iz For i=1, . . . , K
v.sub.i=(r.sup.t.sub.iy.sup.t.sub.i)z For h=1, . . . , H
w.sub.h=(.sub.i(r.sup.t.sub.iy.sup.t.sub.i)v.sub.i h)z.sub.h(1z.sub.h)x.sup.t For i=1, . . . , K
v.sub.iv.sub.i+v.sub.i For h=1, . . . , H
w.sub.hw.sub.h+w.sub.h

(39) until convergence.

(40) FIG. 6 illustrates a system 25 for a user interface for automated artifact filtering for an EEG. A patient 15 wears an electrode cap 31, consisting of a plurality of electrodes 35a-35c, attached to the patient's head with wires 38 from the electrodes 35 connected to an EEG machine component 40 which consists of an amplifier 42 for amplifying the signal to a computer 41 with a processor, which is used to analyze the signals from the electrodes 35 and create an EEG recording 51, which can be viewed on a display 50. A button on computer 41, either through a keyboard or touchscreen button on display 50 allows for the application of a plurality of filters to remove the plurality of artifacts from the EEG and generate a clean EEG. A more thorough description of an electrode utilized with the present invention is detailed in Wilson et al., U.S. Pat. No. 8,112,141 for a Method And Device For Quick Press On EEG Electrode, which is hereby incorporated by reference in its entirety. The EEG is optimized for automated artifact filtering. The EEG recordings are then processed using neural network algorithms to generate a processed EEG recording, a raw score. The processor 41 is also configured to calibrate the raw score to generate a probability value that an event has occurred and then to generate a display of the probability value versus time. Further, the processor 41 is configured to validate the probability value. The processor is also connected to the display for displaying a final output.

(41) The EEG is optimized for automated artifact filtering. The EEG recordings are then processed using neural network algorithms to generate a processed EEG recording which is analyzed for display.

(42) An additional description of analyzing EEG recordings is set forth in Wilson et al., U.S. patent application Ser. No. 13/620,855, filed on Sep. 15, 2012, for a Method And System For Analyzing An EEG Recording, which is hereby incorporated by reference in its entirety.

(43) A patient has a plurality of electrodes attached to the patient's head with wires from the electrodes connected to an amplifier for amplifying the signal to a processor, which is used to analyze the signals from the electrodes and create an EEG recording. The brain produces different signals at different points on a patient's head. Multiple electrodes are positioned on a patient's head. The CZ site is in the center. The number of electrodes determines the number of channels for an EEG. A greater number of channels produce a more detailed representation of a patient's brain activity. Preferably, each amplifier 42 of an EEG machine component 40 corresponds to two electrodes 35 attached to a head of the patient 15. The output from an EEG machine component 40 is the difference in electrical activity detected by the two electrodes. The placement of each electrode is critical for an EEG report since the closer the electrode pairs are to each other, the less difference in the brainwaves that are recorded by the EEG machine component 40. FIG. 7 is a map representing the international 10-20 electrode system for electrode placement for an EEG. FIG. 8 is a detailed map representing the intermediate 10% electrode positions, as standardized by the American Electroencephalographic Society, for electrode placement for an EEG. A more thorough description of an electrode utilized with the present invention is detailed in Wilson et al., U.S. Pat. No. 8,112,141 for a Method And Device For Quick Press On EEG Electrode, which is hereby incorporated by reference in its entirety.

(44) Algorithms for removing artifact from EEG typically use Blind Source Separation (BSS) algorithms like CCA (canonical correlation analysis) and ICA (Independent Component Analysis) to transform the signals from a set of channels into a set of component waves or sources.

(45) In one example an algorithm called BSS-CCA is used to remove the effects of muscle activity from the EEG. Using the algorithm on the recorded montage will frequently not produce optimal results. In this case it is generally optimal to use a montage where the reference electrode is one of the vertex electrodes such as CZ in the international 10-20 standard. In this algorithm the recorded montage would first be transformed into a CZ reference montage prior to artifact removal. In the event that the signal at CZ indicates that it is not the best choice then the algorithm would go down a list of possible reference electrodes in order to find one that is suitable.

(46) An additional description of analyzing EEG recordings is set forth in Wilson et al., U.S. patent application Ser. No. 13/684,469, filed on Nov. 23, 2012, for a User Interface For Artifact Removal In An EEG, which is hereby incorporated by reference in its entirety. An additional description of analyzing EEG recordings is set forth in Wilson et al., U.S. patent application Ser. No. 13/684,556, filed on Nov. 25, 2012, for a Method And System For Detecting And Removing EEG Artifacts, which is hereby incorporated by reference in its entirety.

(47) FIGS. 9, 9A, 9B and 9C illustrate a graphical display of the amount of artifact present in an EEG recording. An artifact intensity channel 110 is shown as a series of horizontal lines 111. The plurality of horizontal lines 111 shown comprises a horizontal line 112 for a muscle artifact, a horizontal line 113 for a chewing artifact, a horizontal line 114 for a vertical eye movement artifact, and a horizontal line 115 for a lateral eye movement artifact. Those skilled in the pertinent art will recognize that more or less horizontal lines may be used without departing from the scope and spirit of the present invention.

(48) Also shown in FIGS. 9 and 9A are a seizure probability channel 120, a rhythmicity spectrogram, left hemisphere channel 130, a rhythmicity spectrogram, right hemisphere channel 140, a FFT spectrogram left hemisphere channel 150, a FFT spectrogram right hemisphere channel 160, an asymmetry relative spectrogram channel 170, a asymmetry absolute index channel 180, an aEEG channel 190, and a suppression ration, left hemisphere and right hemisphere channel 200.

(49) Rhythmicity spectrograms allow one to see the evolution of seizures in a single image. The rhythmicity spectrogram measures the amount of rhythmicity which is present at each frequency in an EEG record.

(50) The seizure probability trend shows a calculated probability of seizure activity over time. The seizure probability trend shows the duration of detected seizures, and also suggests areas of the record that may fall below the seizure detection cutoff, but are still of interest for review. The seizure probability trend when displayed along with other trends, provides a comprehensive view of quantitative changes in an EEG.

(51) As shown in FIG. 12, the EEG machine component 95 preferably is a computer that includes peripheral interfaces 325, an output/A/V 326, a communication/NIC 327, a processor 328, a memory 329, and a storage 330. Those skilled in the pertinent art will recognize that the machine component 95 may include other components without departing from the scope and spirit of the present invention.

(52) A patient has a plurality of electrodes attached to the patient's head with wires from the electrodes connected to an amplifier for amplifying the signal to a processor, which is used to analyze the signals from the electrodes and create an EEG recording. The brain produces different signals at different points on a patient's head. Multiple electrodes are positioned on a patient's head as shown in FIGS. 7 and 8. The number of electrodes determines the number of channels for an EEG. A greater number of channels produce a more detailed representation of a patient's brain activity. Preferably, each amplifier 42 of an EEG machine component 40 corresponds to two electrodes 35 attached to a patient's 15 head. The output from an EEG machine component 40 is the difference in electrical activity detected by the two electrodes. The placement of each electrode is critical for an EEG report since the closer the electrode pairs are to each other, the less difference in the brainwaves that are recorded by the EEG machine component 40. A more thorough description of an electrode utilized with the present invention is detailed in Wilson et al., U.S. Pat. No. 8,112,141 for a Method And Device For Quick Press On EEG Electrode, which is hereby incorporated by reference in its entirety. The EEG is optimized for automated artifact filtering. The EEG recordings are then processed using neural network algorithms to generate a processed EEG recording, which is analyzed for display.

(53) Algorithms for removing artifact from EEG typically use Blind Source Separation (BSS) algorithms like CCA (canonical correlation analysis) and ICA (Independent Component Analysis) to transform the signals from a set of channels into a set of component waves or sources. The sources that are judged as containing artifact are removed and the rest of the sources are reassembled into the channel set.

(54) FIG. 10 shows a flow chart for a method, generally designated 400, of the present invention. A method 400 for validating a seizure probability for an EEG starts at step 401, generating a plurality a plurality of EEG signals. Step 402 is generating an EEG recording from the plurality of EEG signals. Step 403 is submitting the EEG recording to a neural network to generate a raw score. Step 404 is calibrating the raw score to generate a probability value that a seizure has occurred. Step 405 is generating a graph of the probability value versus time. The method 400 further includes validating the probability value (not shown).

(55) FIG. 11 shows a flow chart for a method, generally designated 600, of the present invention. A method 600 for generating a probability value for an event starts at block 601 where multiple training set inputs are generated from a machine comprising a source, a processor and a user-interface. At block 602, the multiple training set inputs are submitted to a recognition algorithm to generate a raw score. At block 603, the raw score is calibrated to generate a probability value that an event will occur. At block 604, a set is validated to test that the probability value is correct. At block 605, the probability values are generated against data submitted for analysis.

(56) From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes modification and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claim. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.